This invention relates to solar fluid heating systems and more particularly to a solar fluid heating system which utilizes a series of valves controlled by temperature and pressure differentials to circulate the fluid through the system.
In the past, there have been various systems designed utilizing solar energy to heat different fluids. However, the majority of the systems, especially the ones having solar collectors elevated gravitationally above the heated fluid storage devices require the use of pumps to circulate the fluids through the system.
The present invention negates the necessity of a circulating pump by using a system of fluid pressure control and temperature control valves to effect the circulation of the fluid through the system. Thus the system requires no pump and no motor and no extra electrical energy is expended.
The prior art also includes thermosyphoned solar water heating systems which although they do not require circulation pumps, do require that the storage tank be at a higher elevation than the solar collector, which, is not necessary with the present invention.
Another advantage of the present invention is that the heated fluid passes through the solar collector only once, always entering the collector at the cold supply temperature and leaving at the desired hotter temperature. This results in a lower average collector temperature and less energy loss through insulation and transparent collector covers. The result is higher collector efficiency.
Also since the fluid passes through the collector only once, small flow rates in the order of only 0.01 gallons per minute per square foot of collector plate area are realized. This enables the majority of all lines, valves and fittings to be either a quarter inch or three-eights inch which is a nominal size for a system designed to operate in conjunction with conventional hot water heaters. This results in significant cost savings in piping, fittings, valves and insulation.